Huge quantities of used post-consumer carpet are landfilled each year. Disposing of whole carpet in this way is not only expensive, but also runs counter to an increasing emphasis on environmental stewardship. Merely discarding whole carpet precludes recycling the useful materials present in post-consumer carpet.
Various mechanical separation processes have been proposed to separate and recover materials from whole carpet. The processes often require complicated and expensive integration of numerous unit operations, and yet achieve modest results. In particular, efforts to recover materials from whole carpet most often subject a feedstock of post-consumer, whole carpet to one of numerous separation techniques. Unfortunately, some materials (e.g., adhesives) and impurities (e.g., dirt) present in used carpet necessitate numerous washing and screening steps. These impede the effectiveness of most separation processes. Reduced efficiency frequently renders recovery of the desired components costly, and thus impractical.
One method for recovering carpet construction materials is hot-wire skimming from the carpet surface (e.g., shearing nylon pile). See e.g., U.S. Pat. No. 6,059,207 (Costello et al.). This approach, however, recovers only the face fiber that extends above the carpet backing. Consequently, it is not an effective method for recovering the significant portion of face fiber found below the carpet backing.
Other processes attempt to separate and refine carpet components by first reducing the size of the whole carpet and thereafter separating the component materials via various unit operations, such as elutriators, centrifuges, hydrocyclones, and settlers. See e.g., U.S. Pat. No. 5,230,473 (Hagguist et al.); U.S. Pat. No. 5,535,945 (Sferrazza et al.); U.S. Pat. No. 5,598,980 (Dilly-Louis et al.); U.S. Pat. No. 5,722,603 (Costello et al.); and U.S. Pat. No. 5,916,410 (Goulet et al.); and U.S. Pat. No. 6,379,489 (Goulet et al.). Each kind of operation carries its own advantages and disadvantages, but as of yet none has been employed in a way that provides cost-effective reclamation of carpet materials.
Each of the aforementioned U.S. patents is hereby incorporated by reference in its entirety.
In contrast to prior carpet reclamation processes, commonly assigned U.S. Pat. No. 6,752,336 (Wingard) discloses cost-effective methods to separate and recover the components of carpet waste, particularly post-industrial, pre-consumer carpet waste. In this regard, U.S. Pat. No. 6,752,336 provides efficient methods for recycling post-industrial, pre-consumer carpet such that the recovered materials are sufficiently pure to facilitate their direct use in other products. Accordingly, the application of aspects of the separation methods disclosed U.S. Pat. No. 6,752,336 to whole carpet materials could provide efficiencies with respect to the reclamation of even post-industrial, post-consumer carpet.